在HTTP请求中获取/设置请求属性

我在android客户端设置了一些键值对，我怎么能在服务器端得到它。

               FileInputStream fileInputStream = new FileInputStream(sourceFile);
               URL url = new URL(upLoadServerUri);
               // Open a HTTP  connection to  the URL
               HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 
               conn.setDoInput(true); // Allow Inputs
               conn.setDoOutput(true); // Allow Outputs
               conn.setUseCaches(false); // Don't use a Cached Copy
               conn.setRequestMethod("POST");
               conn.setRequestProperty("Connection", "Keep-Alive");
               conn.setRequestProperty("ENCTYPE", "multipart/form-data");
               conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
               conn.setRequestProperty("uploaded_file", fileName); 
               conn.setRequestProperty("uploaded_file", fileName);
               conn.setRequestProperty("key_1", "value_1"); 
               conn.setRequestProperty("key_2", "value?_2"); 
               conn.setRequestProperty("key_3", "value_3"); 
               conn.setRequestProperty("key_n", "value_n"); 

如何得到key_1,key_2 ....

我已经尝试了所有这些方法

$_GET['key_1'];
$_REQUEST['key_1'];
$_POST['key_1'];
$_FILE['key_1'];

这些都不适合我，

请大家帮帮我